Impact of intra-operative fluid and noradrenaline administration on early postoperative renal function after cystectomy and urinary diversion: A retrospective observational cohort study.

BACKGROUND The use of noradrenaline to enable a restrictive approach to intra-operative fluid therapy to avoid salt and water overload has gained increasing acceptance. However, concerns have been raised about the impact of this approach on renal function. OBJECTIVES To identify risk factors for acute kidney injury (AKI) in patients undergoing cystectomy with urinary diversion and determine whether administration of noradrenaline and intra-operative hydration regimens affect early postoperative renal function. DESIGN Retrospective observational cohort study. SETTING University hospital, from 2007 to 2016. PATIENTS A total of 769 consecutive patients scheduled for cystectomy and urinary diversion. Those with incomplete data and having pre-operative haemodialysis were excluded. MAIN OUTCOME MEASURES AKI was defined as a serum creatinine increase of more than 50% over 72 postoperative hours. Multiple logistic regression analysis was performed to model the association between risk factors and AKI. RESULTS Postoperative AKI was diagnosed in 86/769 patients (11.1%). Independent predictors for AKI were the amount of crystalloid administered (odds ratio (OR) 0.79 [95% confidence interval (CI), 0.68 to 0.91], P = 0.002), antihypertensive medication (OR 2.07 [95% CI, 1.25 to 3.43], P = 0.005), pre-operative haemoglobin value (OR 1.02 [95% CI, 1.01 to 1.03], P = 0.010), duration of surgery (OR 1.01 [95% CI, 1.00 to 1.01], P = 0.002), age (OR 1.32 [95% CI, 1.44 to 1.79], P = 0.002) but not the administration of noradrenaline (OR 1.09 [95% CI, 0.94 to 1.21], P = 0.097). Postoperative AKI was associated with longer hospital stay (18 [15 to 22] vs. 16 [15 to 19] days; P = 0.035) and a higher 90-day major postoperative complication rate (41.9 vs. 27.5%; P = 0.002). CONCLUSION Noradrenaline administration did not increase the risk for AKI. A too restrictive approach to administration of crystalloids was associated with an increased risk for AKI, particularly in older patients, those receiving antihypertensive medication, and those whose surgery was prolonged. As AKI was associated with longer hospital stay and increased postoperative morbidity, these observations should be taken into account to improve outcome when addressing peri-operative fluid management. TRIAL REGISTRATION Not applicable